Apparatus, fixture, packing, a method for machining of spectacle lenses

ABSTRACT

There is described an apparatus and a fixture used in determining position and for producing assembling holes in a spectacle lens for rimless spectacles. The assembling holes are intended for receiving a U-shaped bracket which is used in fastening bridge and side bar hinge. The apparatus and fixture includes interacting guide pins and guide holes. These guide holes/pins are unambiguously disposed. The guide holes will preferably be placed symmetrically in relation to a hole center line for the lens, when this is placed in the fixation opening of the fixture with the hole center line disposed opposite to markings at the fixation opening. The assembling holes are thus placed symmetrically in relation to the marking. By such a system it is possible to make rimless spectacles that appear very accurate, without special skilled qualifications on the part of the optician to make assembling holes in the lenses.

This application claims the benefit of Danish Application No. PA 200300354 filed Mar. 7, 2003 and PCT/DK2004/000144 filed Mar. 5, 2004, whichare hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention concerns an apparatus for use in determining theposition of and forming of assembling holes in spectacle lenses forrimless spectacles, the assembling holes intended for mounting a bridgeand a side bar hinge, and of the type including a holder for the lensand machining means that are movable, preferably in two dimensions,relative to the holder.

The invention furthermore concerns a fixture for spectacle lenses forrimless spectacles and for use in determining the position of andformation of assembling holes in the lens, the assembling holes intendedfor mounting a bridge and a side bar hinge.

The invention furthermore concerns a packing for use in fixture forspectacle lenses for rimless spectacles and for use in determiningposition of and formation of assembling holes in the lens, theassembling holes being intended for mounting a bridge and a side barhinge, the fixture including an opening for fixing the lens at itscircumferential edge with the packing disposed between the lens and thefixation opening.

Finally, the invention also concerns a method for fixing spectaclelenses for rimless spectacles by determining position of and formationof assembling holes in the lens, and including:

-   -   fixing the lens in a fixture for correct hole centre line        orientation;    -   forming the assembling holes;    -   mounting a bridge and a side bar hinge in the assembling holes;        and    -   moving machining means, preferably in two dimensions, relative        to the holder.

In the industry of spectacle manufacturing, rimless spectacles havehitherto been problematic for the optician to produce. This is due tothat tools and methods up till now put great demands on skill andprecision on the part of the optician making assembling holes formounting bridge and hinge fittings/side bars in the lenses. Among these,a difficulty has particularly appeared at correct positioning of thespectacle lenses in relation to the machining means used for forming theassembling holes. Just a very little turning of axis when positioning alens in relation to the frame of the machining tool has thus caused avery visible skewness when placing assembling holes and thereby alsorisk of a distinct skewness in the formed spectacle.

With the known systems, one also desires to use as thin glasses aspossible due to weight and appearance of the spectacles. When mountingbridge and hinges occurs in such lenses, the thinner the lenses thegreater demands are put on precision.

Furthermore, from the user there are demands to placing the assemblingholes/slits as close to the edge of the lens as possible with regard tothe general appearance and so that fastening members become less visiblein the field of vision. This is particularly the case when the modelsare relatively small.

Usually, when making lenses it is important to be able to place thespectacle lenses with optical centre correctly in relation to the user.Correct positioning is particularly important on small models whereprogressive lenses are used. In such lenses, a slight displacement andvery small axis deflections of 2-3° may produce big sight problems forthe user. By known embodiments, assembling holes in the shape of slitsor round holes positioning systems are placed by manual marking of thelens. In some cases, this also occurs under use of simple drill jigs ormeasuring jigs with basis in manual markings on the lens. This putsgreat demands on skilled measurement, where the precision depends on thecare and the ability residing with the individual optician.

When the optician grinds a lens, there will be tolerances on theso-called box dimensions. Box dimensions are the rectangle where thecircumference of the lens can be ground in. A datum line will appear atthe same time as the centre line of the height of the box dimension.

The optician will typically measure the width in the box. With thetolerances existing for machines used for grinding today, there is riskof tolerance deviation on the height/width of the box dimension.Therefore, there will be a risk of variations in the box dimensions ofthe lens. This often entails that the optician grinds lenses withundersize, meaning in turn that the lens becomes too small in relationto a template. When the optician is subsequently to place assemblingholes in the lens, this occurs by pressing the lens against a sidewallwhere the hole is to be made. However, this gives rise to uncertainty atthe formation of the assembling holes.

SUMMARY OF THE INVENTION

It is the purpose of the invention to relieve the drawbacks hithertoassociated with positioning of and formation of assembling holes inlenses and to provide a system and a method whereby rimless spectaclelenses can be produced very accurately without special, skilledqualifications on the part of the optician.

According to the present invention, this is achieved with an apparatusof the kind mentioned in the introduction, which is peculiar in that theholder includes a fixture having an opening for fixing the lens at itscircumferential rim and which has at least two first guide means thatinteract with two corresponding second guide means on the apparatusframe, and which are disposed unambiguously, preferably symmetrically,in relation to a hole centre line for the lens when the latter is placedin the fixation opening.

According to the invention, the fixture forming part of the system willbe peculiar in that it includes an opening for fixing the lens at itscircumferential edge and at least two first guide means that arearranged for interaction with two corresponding second guide means on aframe in an apparatus in which the fixture will be placed, and which isplaced unambiguously, preferably symmetrically, in relation to a holecentre line for the lens when the latter is placed in the fixationopening.

The method indicated according to the present invention is peculiar inthat the lens is fixed in a fixture having an opening for fixing thelens at its circumferential edge, that the fixture is fixed in anapparatus via at least two first guide means that are brought tointeract with two corresponding second guide means on the apparatusframe, the first guide means being disposed unambiguously, preferablysymmetrically, in relation to a hole centre line for the lens, when thelatter is placed in the fixation opening.

The packing indicated according to the present invention is peculiar inthat the packing is largely rectangular with cut off corners, preferablyfor forming a largely cross-shaped packing, and that the packing isformed by a resilient material.

In the present invention, by hole centre line is meant a line passingthrough a centre point for assembling holes or assembling slits andwhich is parallel with the datum line of the lens. If the assemblingholes are disposed at the centre of a lens, the hole centre line and thedatum line will coincide.

As the fixture has an opening fixing the lens at its circumferentialedge, the risk of axis turning is avoided. The fixing opening will havea position and place in the fixture which is well-defined in relation tothe placing of the first guiding means in the fixture. Hereby it becomespossible to perform a precise disposition of the hole centre line of thelens when it is placed in the fixation opening. This is substantiallydifficult from the prior art where the optician was to fasten the lensaccording to a visual assessment, with a hole centre line oriented fromlines located on a table or a base.

As the fixture has at least two first guide means, two fixation pointsare achieved which unambiguously can define the position of the holecentre line. Preferably, the two first guide means will be placed asopenings or pins which are disposed symmetrically at each their side ofthe hole centre line. These guide means can interact with correspondingguide means on the apparatus frame. Hereby, the position of the lenswill be well defined in relation to the apparatus and thereby also tothe machining means of the apparatus. Thus it is possible to perform avery precise positioning and formation of the assembling holes.

The fixture may be used as a negative lens jig so that the optician canensure that the lens is ground with correct size and shape. Furthermore,marking of the hole centre line in the lens can be aligned with acorresponding marking of the hole centre line in or at the fixationopening in the lens jig, sot that the optician may also ascertain thatthe lens not only has the correct shape but that the hole centre line ofthe lens is also oriented entirely correct in relation to the markingplaced in immediate vicinity of the fixation opening of the fixture. Thecontrol means will thus be disposed symmetrically in relation to themarkings of the fixture for the hole centre line as well as the markingof the lens of the hole centre line.

It is preferred that the control means are disposed symmetrically inrelation to the hole centre line, but it is possible to place them atother unambiguous positions in relation to the hole centre line.

The packing according to the invention enables placing the lens in thefixation opening. The packing will be squeezed by the lens which is thenfixed correctly in the opening with guidance vertically as well aslaterally. As the packing is made without corners, either by cutting offcorners or by making with cross-shape, problems with folding in cornersare avoided, though sufficient guiding of the lens is achieved, as thelongitudinal and side faces on the lens are in contact with the packing.It is preferred that with the packing about 80% of the circumference ofthe lens is covered, however, yet it is possible to have as narrow anextension of the packing material between the cut off corners so that acovering as low as about 60% of the circumference of the lens isattained.

The rubber-elastic material is preferred to have a Shore between 40 and60. The packing material may be produced of an elastomer, of silicone, arubber material or other resilient material.

For most practical purposes, the packing will have a thickness in themagnitude of about 1 mm for use in a fixture made with a dimension whichis nominally about 9/10 mm over the nominal dimension of the lens. Byusing such a combination it is possible to compensate for lensesirrespectively whether they are made undersize or slightly oversizerelative to the exact dimension of the lens.

As an alternative to making a separate packing for laying in thefixture, it will also be possible to make a fixture having an elastic,flexible edge list in the fixation opening. Such an elastic fixationlist in the fixation opening may e.g. be formed of an elastic O-ringwhich is held in a fixation groove inside the circumference edge of thefixation opening. Such a packing may be used for engaging thecircumferential edge of the lens.

According to a further embodiment, the apparatus and the fixture arepeculiar in further including an elastic ring for placing in a fixationopening at a position between the lens and the apparatus frame forfixing the position of the lens in direction perpendicularly to theplane of the fixation opening, as the lens is pressed down against thering which thereby is brought into contact against the frame on whichthe fixture is placed. Hereby is achieved a possibility for correctpositioning of the lens relative to the frame and thereby also relativeto a plane perpendicular to the fixation opening. Thus it is possible tofix the lens spatially during machining, which thereby can be performedvery accurately, not only in the plane of the lens but also indirections perpendicularly thereto, ensuring that inclining assemblingholes for the bridge and side bar hinges are not formed.

According to a further embodiment, the apparatus and fixture arepeculiar in that arms projecting from the ring are provided, and thatthe fixture includes cutouts for accommodating the arms in a fixedengagement. In a simple way is hereby achieved a correct positioning ofthe ring in the fixation opening, and the optician's work is facilitatedby the ring being secured in relation to the fixture.

According to a further embodiment, the apparatus is peculiar in that apressure pad is supported on the frame and arranged displaceable in aplane largely in parallel with the fixture so that it can be disposedopposite to the lens in the fixation opening and displaceable indirection perpendicularly thereto for pressing and fixing the lens in acontact position in the fixation opening. The bearing of the pressurepad against the lens will occur in the so-called box centre.

According to a further embodiment, the apparatus and fixture arepeculiar in that first and second guide means are guide pins and guideholes, respectively. Hereby is achieved technically simple means forpositioning the fixture. The fixture will be held in place by the forceof gravity when the guide pins are placed in the guide holes. The guideholes will preferably be placed in the fixture.

If the fixture is a moulded plastic article, the guide holes and thefixation opening may be formed at the moulding, so that the fixture canbe moulded in large series with exact shape which the optician can usewithout any need for machining or adaptation.

Alternatively, the guide holes and fixation opening can be formed bymachining a pre-form or blank.

According to a further embodiment, the apparatus and fixture arepeculiar in that the fixture has opposing side faces, and that thefixation opening is a through-going opening between these side faces,and that there is provided first control means on both side faces.Hereby, there will only be need for one fixture for a right and a leftspectacle lens, irrespectively if the two spectacle lenses are identicalor not.

According to a further embodiment, the fixture is peculiar in that itincludes a packing for disposition between the lens circumferential edgeand the fixation opening which is oversized in relation to the lens.Hereby, the need for tolerances in the lens box dimensions and risk ofimprecise positioning of the assembling holes is reduced. The dimensionsfor the fixation opening may nominally be greater than the lensdimension, e.g. with 9/10 mm over the lens dimension. It may be saidthat the packing acts as compensating means for the oversize of thefixation opening.

The optician turns the fixture with one side facing the apparatus framewhen machining one lens and with the other side face facing the framewhen machining the other lens. This is possible as spectacle lenses willnormally always be symmetrical, irrespectively whether they areidentical or not. By using one fixture for both lenses, it isparticularly ensured that the formed, rimless spectacle will besymmetrical, without demanding special skilled abilities on the part ofthe optician.

With the method according to the invention, there will always be asecure positioning of the lens so that the hole centre line is placedcorrectly when the lens is placed in the fixation opening. The guidemeans of the apparatus interacting with the guide means on the fixturewill ensure the correct position for the subsequent formation of theassembling holes.

If by the method a separate packing is used, this will be disposed overthe fixation opening before the lens is pressed in. Hereby, the lens ispressed into the fixation opening simultaneously with the packing beingclamped between the circumferential edge of the lens and the inner sideof the fixation opening of the fixture. The fixture is then placed inthe apparatus, and assembling holes are formed in the way which isanalogous to the way by which the assembling holes are formed in a lensmounted in the fixture without using the packing.

DESCRIPTION OF THE DRAWINGS

The invention will now be explained more closely with reference to theaccompanying drawing, where:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a fixture according to the invention;

FIG. 2 shows a cross-section through the fixture shown in FIG. 1,

FIG. 3 shows a perspective view of an apparatus according to theinvention for use together with the fixture shown FIGS. 1 and 2;

FIG. 4 shows a perspective view corresponding to FIG. 3 but with thefixture placed on the frame of the apparatus;

FIG. 5 shows a schematic, partial view of a detail in the apparatusshown in FIG. 4 for illustrating securing of a lens in the fixture;

FIG. 6 shows a perspective view corresponding to FIG. 4 for illustratingthe apparatus under formation of assembling holes in the lens;

FIG. 7 shows a perspective view of the apparatus during turning thefixture for forming additional assembling holes in the lens;

FIG. 8 shows perspective views for illustrating turning the fixture inorder to fix another symmetric spectacle lens in which assembling holesare to be formed subsequently;

FIG. 9 shows a perspective view through an assembling hole in a lens anda plan view of the assembling hole with a U-shaped bracket placedtherein; and

FIGS. 10-16 show views corresponding to FIGS. 1-7 for illustrating themethod for forming assembling holes during use of a packing in thefixture.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, identical or corresponding elements in different FIGS.will be provided the same designations, and therefore no explicitexplanation to all elements in each FIG. will be given. Also, there willnot be given any specific explanation to the parallel elements in FIGS.10-16. Also here will be given an explanation to the differenceoccurring by using a packing together with the fixture in contrast tousing a fixture without a packing, as illustrated in FIGS. 1-7.

In FIG. 1 is seen a fixture 1 with a fixation opening 2 for fixing aspectacle lens 3 by bringing the circumferential edge 4 of the lens incontact with the inner circumferential edge 5 of the fixation opening 2.The fixture is provided with guide means in the form of guide holes 6.The guide holes 6 are provided in pairs symmetrically about a holecentre line 7 for the lens when the latter is placed in the fixationopening 2. By being placed in the fixation opening 2, the hole centreline 7 will be located opposite to a marking 8 that indicates where thehole centre line is to be when the lens is placed in the fixture.

An elastic ring 9 is provided with two projecting arms 10. The fixture 1is provided with cutouts 11 for accommodating the arms 10 so that theelastic ring is located in the fixation opening.

By placing the ring 9 in the fixation opening, the lens 3 can bedisposed correctly as illustrated in the cross-section shown in FIG. 2.The arrow 12 illustrates how the lens 3 is displaced into the fixationopening 2 until it is bearing against the ring 9. The ring 9 will besecured in relation to the fixture, as the arms 10 will be of an elasticmaterial and have a size which is slightly greater than the cutouts 11so that they are elastically secured in relation to the fixture.

FIG. 3 shows how the fixture 1 with the lens located therein is placedin an apparatus which is generally designated 13 and which includes aframe 14 on which the fixture 1 is placed. The frame 14 is provided withguide pins 15 that interact with the guide holes 6 in the fixture 1. Thefixture and thereby also the lens are hereby disposed correctly inrelation to machining means in the shape of a drilling machine 15 whichis provided with a drill 16 used for forming assembling holes 17 (seeFIG. 9) in the lens. The assembling holes 17 are, as it appears fromFIG. 9, intended for receiving a U-shaped bracket 18 which in a knownway is fastened in the assembling hole 17 due to the elastic force inthe bracket that is used for mounting of use and side bar hinges. Thusassembling holes are 17 are provided at each side of a lens.

The machining apparatus shown in FIG. 3 includes an operating handle 19which is used for moving the drill 16 up and down. Furthermore, thedrill is suspended in a pivotable column 20. The pivotability for thedrill 16 is limited as the drilling machine only can be displacedbetween two adjustable stops 21 (only one is visible in FIG. 3). Byforming an assembling hole, the drill diameter determines the width ofan assembling hole 17, and the setting of the stops 21 defines thelength of the assembling hole. When the fixture 1 is placed on theapparatus frame 14, the elastic ring 9 will bear against the frame 14.In order to secure the lens 3 in correct position in the fixationopening 2, the apparatus is provided with a pressure pad 22. This issupported in a support holder 23 mounted displacing in a groove 24 inthe apparatus 13.

As indicated by an arrow 25 in FIG. 4, the pressure support holder 3 isarranged on a pivoting pressure pad, from a neutral position where thefixture is readily placed on the frame 14, to a position where thepressure pad 22 is situated opposite to the ring 9. By pivoting thesupport holder 23 the arm 26 is thus brought from a position where thearm 14 is free, to a position in over the fixture when the latter isplaced on the frame, as shown in FIG. 4. Then an axial displacement ofthe pressure pad 22 is performed down against the lens 2 by turning ascrew-threaded head 27 in the support holder 23. Hereby, the pressurepad 22 is pressed down against the lens 3 so that it is secured betweenthe pressure pad 22 and the ring 9 in a correct position. The correctposition for the pressure pad 22 will be a bearing against the lens inthe box centre.

As it appears from FIG. 5, the pressure pad 22 and the ring 9 will beplaced around a common axis 28 so that a skew pressure on the lens 3will not occur. In this position, the table 16 will be positionedopposite to the intended position for an assembling hole.

FIG. 6 illustrates formation of an assembling hole 17 in the lens 2. Anarrow 29 indicates that the user presses the handle forward whereby thedrill 16 is displaced downwards and drills a hole in the lens 2. Sincethe drilling machine 15 can be swung between two extreme positionsdefined by the stops 21, the side of the drill 16 will cut an oblongslit in the lens when the user pivots the drilling machine 15 from sideto side. This operation is indicated by the arrows 30 where it appearsthat up- and downward motions 31 are performed with the drill and alateral movement 32 in relation thereto.

As alternative to a slit-shaped assembling hole 17, it is possible toform two juxtaposed, round assembling holes (not shown). Fasteningbridge and hinges may hereby be effected with two holes or one hole anda groove in the circumferential edge of the lens. It is necessary tohave two holes at each fastening element for the sake of absorbingmoment. The formation of a slit is thus just a possible design of theassembling hole 17 for interacting with the above mentioned U-shapedbracket 18.

FIG. 7 illustrates that the pressure pad 22 is released and that thesupport holder 23 is pivoted to its position outside the frame 14. Thefixture 1 may hereby be lifted free of the frame 14 as indicated by thearrow 33. Then the fixture is turned as indicated by the arrow 34. Inthis way, a side face 35 of the fixture will still face up against thetool, whereas a side face 36 will be placed against the frame 14.

It is here remarked that the fixture advantageously is formed with fourguide holes 6 for interaction with the guide pins 15. By forming thefirst assembling hole 17 in the lens, the guide holes 6 disposed at afirst longitudinal edge 37 will engage the guide pins 15. After theturning according to the arrow 34, the guide holes 6 at an oppositelongitudinal edge 38 will be brought into engagement with the guide pins15. In this position, the lens 2 will be placed correctly for formingthe second assembling hole in the lens when the fixture, as indicated bythe arrow 39, is placed on the arm 14.

It is noted that in the above explanation, reference is made to guideholes 6, and that in the shown illustration these are placed at the sideface 35 of the fixture. In reality, it will be guide pins 6 which areplaced at the side face 36 of the fixture which is brought intoengagement with the guide pins. However, the guide pins 6 will beprovided as through-going holes, but may alternatively be provided asvarious bottom holes at the side faces 35, 36 of the fixture 2.

After the above mentioned turning of the fixture, the above describedoperations with the intention of clamping the lens and forming theassembling hole are repeated. Then the lens is released again, and thefixture 1 is lifted off the frame. The lens will now be provided withthe two assembling holes for mounting bridge and side bar hinge.

The fixture is formed with a through-going fixation opening 2. Thismeans that a symmetrical spectacle lens together with the firstmentioned lens are to be used for making a spectacle also can beprovided with assembling holes by using the same fixture. It is onlynecessary to remove the ring 9 from the cutout 11 at the side face 36and as indicated by the 39 in FIG. 8 move the ring 9 to the opposingside face 35 and place the arms 10 in the cutouts 11 at the side faces35. Then the lens is turned 180° as indicated by the arrow 40. Then theside face 36 will face upwards against the machining tool, and a lens,which is symmetrical relative to the first lens, can now be placed inthe fixation opening 2 by a method as described above. Then assemblingholes can be formed in a way corresponding to that described above.

By correct positioning of the spectacles, not only a situation withoutrisk of turning the axis can be achieved. Furthermore, a very certainposition of the assembling holes is achieved. Hereby, it becomespossible to make the assembling holes 17 and place them very close tothe circumferential edge 4 of a spectacle lens, in the way appearingfrom FIG. 9. Thus there will be no risk of the assembling hole 17 beingplaced inadvertently close to the circumferential edge 5 so that thereis risk that the lens 3 does not have the required strength propertiesat the subsequent mounting of the U-shaped bracket 18.

FIG. 10 corresponds to FIG. 1, but it is shown here how a packing 41 isplaced between the lens 3 and the fixture 1. In FIG. 11 is illustratedhow the packing 41 is displaced according to the arrow 42 into thefixation opening 2 when the lens 3 according to the arrow 12 is placedagainst the top side of the packing 41 and pressed into the fixationopening 2.

The packing 41 is cut off at the corners 43 so that cross-shaped arms 44are formed. The cruciform arms will cover about 80% of thecircumferential edge 4 of the lens. The cruciform arms 44 will bear onthe longitudinal edges 45 of the lens and the side edges 46 of the lens,respectively.

After the lens 3 has been placed in the fixture 1, as illustrated inFIG. 11, the fixture 1 is placed in the apparatus 13 as illustrated inFIG. 12. Subsequently, the pressure pad 22 is swung in and fixes thelens, as illustrated in FIGS. 13 and 14. After that, the assemblingholes 17 are formed as illustrated in FIGS. 15 and 16 by turning thefixture as described above.

By using the packing 41 as illustrated in FIGS. 10-16, it is possible tosecure the lens 3 in the fixation opening 2 in a fixture in a resilientway, where the fixation opening 2 is oversized and where there will bereduced requirements to tolerances for the fixation opening 2 and thelens 3.

1. Apparatus for use in determining the position of and forming ofassembling holes in spectacle lens for rimless spectacles, theassembling holes intended for mounting a bridge and a side bar hinge,including a holder for the lens and machining means that are movable, intwo dimensions, relative to the holder, wherein the holder includes afixture having an opening for fixing the lens at its circumferential rimand at least two first guide means that interact with two correspondingsecond guide means on an apparatus frame, wherein the first guide meansare disposed unambiguously, symmetrically, in relation to a hole centreline for the lens when the latter is placed in the fixation opening thatit further includes an elastic ring for placing in a fixation opening ata position between the lens and the apparatus frame for fixing theposition of the lens in direction perpendicularly to the plane of thefixation opening, as the lens is pressed down against the ring whichthereby is brought into contact against the frame on which the fixtureis placed and it includes a packing to be placed between thecircumferential edge of the lens and the fixation opening which isformed oversized in relation to the lens.
 2. Apparatus according toclaim 1, wherein there is provided arms extending from the ring, and thefixture includes cutouts for accommodating the arms in a fixedengagement.
 3. Apparatus according to claim 1, wherein a pressure pad issupported on the frame and arranged displaceable in a plane largely inparallel with the fixture so that it can be disposed opposite to thelens in the fixation opening and displaceable in directionperpendicularly thereto for pressing and fixing the lens in a contactposition in the fixation opening.
 4. Apparatus according to claim 1,wherein the first and the second guide means are guide pins and guideholes, respectively.
 5. Apparatus according to claim 1, wherein thefixture has opposed side faces, and that the fixation opening is athrough-going opening between these side faces, and the first guidemeans are provided on both side faces.
 6. Fixture for spectacle lens forrimless spectacles and for use in determining the position of andformation of assembling holes in the lens, the assembling holes intendedfor mounting a bridge and a side bar hinge, wherein the fixture includesan opening for fixing the lens at its circumferential edge and at leasttwo first guide means that are arranged for interaction with twocorresponding second guide means on a frame in an apparatus in which thefixture will be placed, wherein the first guide means is placedunambiguously, symmetrically, in relation to a hole centre line for thelens when the latter is placed in the fixation opening that it furtherincludes an elastic ring for placing in the fixation opening in aposition between the lens and the apparatus frame for fixing theposition of the lens in direction perpendicularly to the plane of thefixation opening, as the lens is pressed down against the ring which isthereby brought in contact against the frame on which the fixture isplaced and it includes a packing to be placed between thecircumferential edge of the lens and the fixation opening which isformed oversized in relation to the lens.
 7. Fixture according to claim6, wherein the fixture has opposing side faces, and that the fixationopening is a through-going opening between these side faces, and thefirst guide means are provided on both side faces.
 8. Fixture accordingto claim 6, wherein it includes a packing for placing between the lenscircumferential edge and the fixation opening which is oversized inrelation to the lens.
 9. Packing for use in fixture for spectacle lensfor rimless spectacles and for use in determining position of andformation of assembling holes in the lens, the assembling holes beingintended for mounting a bridge and a side bar hinge, the fixtureincluding an opening for fixing the lens at its circumferential edgewith the packing disposed between the lens and the fixation opening,wherein the packing is largely rectangular with cut off corners, forforming a largely cross-shaped packing, and the packing is formed by aresilient material.
 10. Method for fixing spectacle lens for rimlessspectacles by determining position of and formation of assembling holesin the lens, and including: fixing the lens in a fixture for correcthole centre line orientation; forming the assembling holes; mounting abridge and a side bar hinge in the assembling holes; and movingmachining means, in two dimensions, relative to the holder, wherein thelens is fixed in a fixture having an opening for fixing the lens at itscircumferential edge as a packing is placed between the circumferentialedge of the lens and the fixation opening which is formed oversized inrelation to the lens that the fixture is fixed in an apparatus via atleast two first guide means that are brought to interact with twocorresponding second guide means on an apparatus frame, the first guidemeans being disposed unambiguously, symmetrically, in relation to a holecentre line for the lens, when the latter is placed in the fixationopening that an elastic ring is placed in the fixation opening at aposition between the lens and the apparatus frame for fixing theposition of the lens in direction perpendicularly to the plane of thefixation opening, as the lens is pressed down against the ring whichthereby is brought into contact against the frame on which the fixtureis placed.